Electrically Conducting and Mechanically Strong Graphene–Polylactic Acid Composites for 3D Printing

Abstract

The advent of 3D printing has had a disruptive impact in manufacturing and can potentially revolutionize industrial fields. Thermoplastic materials printable into complex structures are widely employed for 3D printing. Polylactic acid (PLA) is among the most promising polymers used for 3D printing, owing to its low cost, biodegradability, and nontoxicity. However, PLA is electrically insulating and mechanically weak; this limits its use in a variety of 3D printing applications. This study demonstrates a straightforward and environment-friendly method to fabricate conductive and mechanically reinforced PLA composites by incorporating graphene nanoplatelets (GNPs). To fully utilize the superior electrical and mechanical properties of graphene, liquid-exfoliated GNPs are dispersed in isopropyl alcohol without the addition of any surfactant and combined with PLA dissolved in chloroform. The GNP–PLA composites exhibit improved mechanical properties (improvement in tensile strength by 44% and maximum strain by 57%) even at a low GNP threshold concentration of 2 wt %. The GNP–PLA composites also exhibit an electrical conductivity of over 1 mS/cm at >1.2 wt %. The GNP–PLA composites can be 3D-printed into various features with electrical conductivity and mechanical flexibility. This work presents a new direction toward advanced 3D printing technology by providing higher flexibility in designing multifunctional 3D printed features.

Great enhancement of mechanical features in PLA based composites containing aligned few layer graphene (FLG), the effect of FLG loading, size, and dispersion on mechanical and thermal properties

“…The optical micrographs show “disturbed” flat arrangement of the flakes at upper site due to the presence of larger polymer domains that inhibit the charge transport. The measured conductivity, 5 × 10 −3 S/cm, is higher or comparable with the values reported for PLA composites containing rGO or GP additives (at the same filler amount) 9,24,25 and slightly higher than the one obtained previously for PVA‐FLG (3%) 21 …”

Highly flexible graphene nanoplatelet-polydimethylsiloxane strain sensors with proximity-sensing capability

“…The graphene ink was sonicated for 100 min at room temperature to exfoliate the GNPs and prevent aggregation. AFM measurements revealed that the GNPs in IPA were~5 μm in lateral size and~3.23 nm in thickness, as previously reported [40].…”

A Review of 3D Printing Technologies for Soft Polymer Materials

“…Conductivity is indispensable for flexible and wearable electronics. Conductive organic/inorganic additives, such as carbon nanotubes (CNTs), [192,193] graphene, [194,195] and polypyrrole, [196] are widely used to modify soft polymers. Wei et al [192] developed a printable CNT-PDMS (polydimethylsiloxane) ink that shows good conductivity and stretchability (Figure 7A).…”

“…Wei et al [192] developed a printable CNT-PDMS (polydimethylsiloxane) ink that shows good conductivity and stretchability (Figure 7A). Wu et al [194] and Kim et al [195] added graphene to polyborosiloxane (PBS) and polylactic acid (PLA) to obtain conductive polymers, respectively. Darabi et al [196] presented a 3D printable poly (acrylic acid)-chitosan-polyrrole hydrogel, in which the conductive nano structure of polypyrrole networks provides bulk conductivity (Figure 7B)).…”